@

The @ sign is used to call out usernames in Tweets: “Hello @twitter!” People will use your @username to mentionMentioning other accounts in your Tweet by including the @ sign followed directly by their username is called a “mention”. Also refers to Tweets in which your @username was included. you in Tweets, send you a message or link to your profileYour profile displays information you choose to share publicly, as well as all of the Tweets you've posted. Your profile along with your @username identify you on Twitter..